I have to agree, it seems like theres more issues than just your money. Bitch is crazy!
j/k
Next time she wants to go out for dinner or lunch or whatever just tell her you cant because your broke. See if SHE will actually pay.
Honestly, I've been where you are. I was able to work my way out of it (the situation AND the relationship) and ended up with a damn good friend because of it. Maybe thats something you should consider with this girl, just being friends. Go find someone else thats going to treat YOU good too. It feels great when the girl your with buys you something once in a while too, even if its just a drink or two. Trust me. Relationships wont succeed unless theres atleast a little equality.